Emergency pump



April 27, 1948,

6. HOLLEY, JR

EMERGENCY PUMP Filed Feb. l, 1946 Georgi: ML OZZByJIZ INVENTOR,

Patented Apr. 27, 1948 EMERGENCY rum George M. Holley, In, Grosse Pointe,

signor to George M. Holley and Earl Holley Application February 1, 1948, Serial No. 644,835 r 2'Claims. (01. 103-11) In the control of a gas turbine and specifically in the control of a gas turbine as used to drive a plane, a very dangerous situation develops the moment the fuel pump fails. The object of this invention is to provide a pump which is available to step in and act promptly when the primary or normally operating pump fails.

Immediately after the failure of the primary pump, the emergency pump must take its place,

so that fuel flows to the engine, there being no reserve supply of fuel as in a float chamber.

Figure 1 shows diagrammatically the preferred form of my invention.

Figure 2 shows more in detail the arrangements of the parts illustrated in the outline of Figure 1.

In Figure 1, ID is the emergency pump, I2 is the primary pump, I4 is the fuel pipe leading to both pumps, I6 is the selector valve, I8 is the return pipe from the selector valve, which normally bypasses the fuel that the, emergency pump supplies. Pipe 20 is connected to a port uncovered by the valve l6 and leads to a chamber 54 which communicates through a pipe 24 which leads to the governor control 22. 26 is the fuel line connecting the pump In to the selector valve I6, 20 is the emergency fuel line leading to the governor control 22. 24 is the normal fuel outlet leading from the two fuel pumps Ill and i2 to the governor control 22. 28 is the fuel outlet leading to the gas turbine combustion chamber or to a Diesel engine, which engine also responds directly to fuel flow. The pipe 28 could also supply fluid to any prime mover or to any secondary mover operated by the primary pump.

In Figure 2, as before, I is the emergency pump, I2 is the primary pump, I4 is the fuel supply pipe, I6 is the selector valve, I8 is the return line for the emergency pump, 22 is the governor-controlled mechanism, which controls the speed of the engine by returning excess fuel to the supply line l4 through the line l8 and [4.

The selector valve I6 is connected to the diaphragm 30 and is pushed down by the spring 32 and is drawn up by the differential suctionin venturi 34; a bypass 36 connects the pressure below the venturi 34 with the throat of the venturi. Restrictions 38 and 40 are provided for obvious reasons. An orifice 42 equalizes the pressure above and below the valve I6. 44 is the return pipefrom the governor control '22, which contains a venturi 46 and a diaphragm 48, which controls a balanced valve 50, which regulates the flow to the discharge outlet 28 by in the position shown in broken lines.

. 2 1 returning a portion of the flow through the return pipe 44. r A valve 52 seated in the chamber 54 by a spring 5| closes when the pump 12 quits to prevent a leak back through pump l2.

Operation When the pumps are normally operating, that is to say, when pump I2 is functioning correctly, there is sufllcient flow in the venturi 34 to provide a suction in the throat, which suction acts on the diaphragm 39 and the pressure on the diaphragm 3ll compresses the compression spring 32. When the compression spring 32 is compressed, the selector valve I6 is raised Thereupon, the emergency pump I0 is bypassed through the passage 26, I8 and Id. The fuel merely flows through pipe 26, past the valve it, down the passage l8. Should the pump i2 fall for any reason, then the compression spring 32 pushes the valve I6 down in the position in which it is-shown, because the valve 52 is closed by the compression spring 5| and the discharge from the emergency pump I0 flows by the valve l6 along the passage to the outlet 24. The mechanism shown in the chamber 22 is no part of this invention-merely illustrated to show the practical application of this invention.

What I claim is:

1. An emergency fuel pump having a normally open escape valve in combination with a normally-functioning fuel supply pump having a Venturi outlet, yieldable means for closing said escape valve, means responsive to the drop in pressure in the throat of said venturi, outlet for opening said escape valve against said yielding means when said normally-functioning fuel pump is operating normally, said escape valve being adapted when closed by said yleldable means to also admit fuel from said emergency fuel pump downstream from said Venturi outlet when the flow through said venturi fails, a nonreturn valve in the outlet from said venturi.

2. A primary fuel pump, an emergency pump, an escape valve for said emergency pump, a dia phragm connected to said escape valve, a restriction in the outlet from said primary pump, means responsive to the drop in pressure at said restriction to open said escape valve whereby the discharge from said emergency pump flows past said escape valve, said escape valve being adapted to direct the discharge from said emergency pump into the outlet from said primary pump when said primary pump fails, a nonreturn valve adjacent to said restriction in the outlet from said primary fuel pump to prevent The following references are of record in the file of this patent:

UNITED STATES PATENTS a reversal of flow through said primary pump Number Name Date from said emergency pump. 3 I Small 7. 1928 GEORGE M. HOLLEY, JR, 5 2,243,918 Parker -r June 3, 1941 r 2,255,589 Johnson Sept. 9, 1941 REFERENCES CITED 2,387,531 Rose Oct. 23, 1945 

